Most tornadoes ever in a day?
The extent of damage left behind by a string of deadly tornadoes in Minnesota last week is not yet known, but early glimpses suggest it could be a day for the history books.
The Minnesota Department of Public Safety recorded 39 tornadoes Thursday - a number the National Weather Service is working to confirm.
Previously, the most tornadoes on a single day in Minnesota was on June 16, 1992, when there were 27 tornadoes. That included an F-5 tornado - considered the worst kind - in Chandler, located in the southern part of the state, according to statistics from the state climatology office at the University of Minnesota.
"The scope of the geographic impact of this disaster is as large as any we've seen," Gov. Tim Pawlenty said Friday after touring the Wadena area by helicopter.
Three people died Thursday - a relatively high number considering there have only been seven tornado deaths in Minnesota the past 16 years, climatology statistics show.
Minnesota's deadliest tornado on record was on April 14, 1886. It destroyed parts of St. Cloud and Sauk Rapids and left 72 dead in its wake, statistics note.
By comparison, North Dakota's deadliest tornado was 53 years ago today - June 20, 1957. That tornado killed 10 people and injured more than 100 others. In addition, more than 1,300 homes were damaged or destroyed, with some completely wiped away, according to published reports.
Over the course of time, the number of deaths resulting from tornadoes has decreased. A major reason for that is improved technology and communication, said Brad Hopkins, a meteorologist for the National Weather Service out of Grand Forks.
Doppler radar allows meteorologists to see the motion within a storm. Therefore, they can tell sooner if a tornado is likely, Hopkins said. That, in turn, gives local authorities more time to get the word out and the public more time to seek shelter.
But a tornado doesn't have to have mass casualties to be colossal.
The tornado that swept through the St. Peter, Minn., area on March 29, 1998, is one that won't soon be forgotten. It resulted in two reported deaths and widespread devastation. Fourteen tornadoes touched down that day, one of which was an F-4 in magnitude, according to National Weather Service statistics.
St. Peter, home to Gustavus Adolphus College, was flattened in parts, uprooting the tree-lined landscape that once decorated the city. Much of nearby Comfrey also was destroyed.
Of course, those tornadoes also were memorable because of when they occurred. It's rare for Minnesota to have a tornado as early as March. Historically, June is the month when most tornadoes hit. The time most likely for them to occur is between 2 and 9 p.m., the climatology office reports.
Another massive tornado still on the minds of many in this region is the Aug. 26, 2007, tornado in Northwood, N.D., in southwest Grand Forks County. This tornado, according to official statistics from the National Climatic Data Center, also was an F-4.
Ninety percent of the roughly 460 homes were damaged, and one person died in a mobile home.
The Northwood area also was affected by Thursday's tornadoes.
Hopkins said he can't say for sure when the official reports on these recent tornadoes will be done, as it can be a lengthy process.
The National Weather Service sent three teams out to survey the damage. From there, they'll review their findings and issue a determination on the magnitude.
The teams look at the damage and consider how the buildings were constructed when making an assessment, Hopkins said. That information gives them an idea of what the wind speed likely was at the time of the tornado.
Hopkins said it's too soon to tell where Thursday's tornadoes will rank in Minnesota history.
"Every storm damage survey will reveal a different pattern of destruction," he said. "Every storm is going to be unique."